Devices used to administer a fluid inside the anatomy of a patient are well known. For example, hypodermic needles, catheters, and the like are often used to deliver medication and other fluids to targeted sites within the body. In many instances, catheters are preferred because they can deliver fluid to a particular site over a period of time. Since catheters are generally made of a flexible plastic material, a needle is typically used to insert the catheter within a patient. For example, certain catheters, generally referred to as “through-the-needle” catheters, often require stiff, hollow introducer needles for placement within the anatomy. Thus, the catheter can be inserted through the needle after the needle is located at the targeted site. Typically, such introducer needles have sharp tips that may damage tissue and/or nerves during their delivery into a body, thus causing discomfort for the patient.
Another type of catheters, generally referred to as “over-the-needle” (OTN) catheters, include a catheter coaxially mounted onto a needle. In this type of catheter, the catheter and the needle may be inserted into a patient together. Once the catheter and the needle are located at the targeted site, the needle can be removed, leaving the catheter in place. Thus, OTN catheters can be purposely directed to a targeted site within a patient without the need to thread the catheter therethrough. Accordingly, OTN catheters have gained increased attention in regard to delivering anesthetic medication, for example, for the purposes of nerve block.
A typical OTN catheter is shorter than its internal needle so as to not interfere with inserting the distal end of the needle into a patient. It is desirable, however, for the catheter to be the same length as the needle (or longer) such that the distal end of the catheter can be located more proximate to a nerve bundle for purposes of nerve block.
Accordingly, the present invention is directed to an expandable OTN catheter that addresses the aforementioned problems.